Expose angle removal constraint for connections to user

[wouterjdb]

We currently have a hard-coded constraint that a triangle create by the Delaunay triangulation will removed if it has an angle larger than 150 degrees.

flownet/src/flownet/network_model/_generate_connections.py

Line 50 in 6eb0fd5

> 150

This seems to lead to a lot of duplicate connections in the case of multiple connections per well:

After changing the angle to 80 (maybe a bit too strict), the same area looked like:

By letting the user tweak this number the number of duplicate connections could be reduced significantly.